Stepping into an online casino can feel like entering a foreign country—they have their own currency, their own etiquette, and their own language.

From “RTP” and “Variance” to specific mechanics like “Cascading Reels” and regulatory terms like “Source of Wealth,” the terminology is the fine print that dictates your gaming experience. Understanding these terms is the first step toward playing smarter, spotting bad deals, and protecting your bankroll.

This guide covers the A-Z terms every online player needs to know.

A – C: The Essentials & Mechanics

• Account Verification: The process of proving your identity to the casino to unlock withdrawals. (See also: KYC).
• Affiliate: A third-party website (like this one) that reviews casinos and directs players to them. Affiliates often negotiate exclusive bonuses for their readers that aren’t available directly on the casino’s homepage.
• Ante: An initial mandatory bet is required in card games like Poker before any cards are dealt.
• Auto-Play: A feature in slot games that allows you to set a specific number of spins to play automatically at a set bet level. Note: In some strictly regulated jurisdictions (like the UK), this feature is banned.
• Avalanche Reels (Cascading Reels): A slot mechanic where winning symbols explode or disappear, allowing new symbols to fall into the empty spaces. This allows for multiple consecutive wins from a single spin.
• Bankroll: The total amount of money you have set aside specifically for gambling. Effective bankroll management involves never betting money you cannot afford to lose.
• Bonus Buy (Feature Buy): A mechanic in high-volatility slots where you can pay a premium (usually 50x–100x your stake) to trigger the bonus round immediately, skipping the base game.
• Bonus Hunt: A strategy where a player collects multiple bonuses with a raw balance, saves the bonus rounds, and opens them all at once. Always check T&Cs, as some casinos prohibit this.
• Burn Card In card games, the top card of the deck is “burned” (discarded) by the dealer before dealing to prevent players from knowing what the next card is.
• Cashback: A type of bonus where the casino returns a percentage of a player’s net losses over a specific period (e.g., “10% Cashback on Weekend Losses”).
• Cashout: The act of withdrawing your winnings from the casino to your bank account.
• Cluster Pays: A slot mechanic where wins are generated by groups of matching symbols touching each other (vertically or horizontally) rather than landing on specific paylines.
• Comp Points Loyalty points earned for every real money wager. These can usually be exchanged for cash, bonuses, or merchandise.
• Cooling-Off Period: A responsible gambling tool allowing a player to lock their account for a short time (e.g., 24 hours or 7 days) to take a break.
• Crash Game: A modern genre of crypto-casino game (like Aviator) where a multiplier increases rapidly, and the player must cash out before the game “crashes” to zero.
• Crypto Casino: An online casino that accepts cryptocurrencies like Bitcoin, Ethereum, or Litecoin for deposits and withdrawals.

D – G: Gameplay & Psychology

• Dead Spin: A spin on a slot machine that results in zero winnings.
• Demo Mode (Free Play): A version of a game where you play with “fun money” to test the mechanics. You cannot win real money in this mode.
• Deposit Match: A welcome offer where the casino matches your deposit by a certain percentage (e.g., “100% up to $500”).
• Double Down: A Blackjack move where you double your initial bet in exchange for receiving exactly one more card.
• eCOGRA eCommerce Online Gaming Regulation and Assurance. An independent testing agency that audits online casinos to ensure fair play and player protection.
• Edge (House Edge): The mathematical advantage the casino has over the player, expressed as a percentage. If a game has a 5% house edge, the casino keeps $5 in profit on every $100 bet in the long run.
• Expanding Wilds: A Wild symbol that expands to cover an entire reel, increasing the chance of hitting winning combinations.
• Gambler’s Fallacy: The mistaken belief that if an event happens frequently during a period, it will happen less frequently in the future (e.g., “Red has hit 10 times in Roulette, so Black is due”).
• Game Weighting: How much a specific game contributes toward bonus wagering requirements. Slots usually contribute 100%, while high-RTP table games like Blackjack may only contribute 10% or 0%.
• Gamification: The addition of video game-like elements to a casino, such as leveling up, completing missions, or fighting “bosses” to earn rewards.
• Grind: Playing with small bets for a long period, usually to clear a wagering requirement with minimal risk.

H – L: High Rollers & Live Play

• Hand: The cards held by a player or dealer in a single round of a card game.
• High Roller: A player who consistently wagers large sums of money. (See also: Whale).
• Hit Frequency: A percentage describing how often a slot machine stops on a winning combination. High hit frequency = frequent small wins. Low hit frequency = rare but larger wins.
• House Rules: The specific rules of a game as defined by that particular casino (e.g., whether the dealer hits or stands on Soft 17 in Blackjack).
• Insurance: A side bet in Blackjack offered when the dealer’s face-up card is an Ace. It pays 2:1 if the dealer has Blackjack.
• Jackpot (Progressive): A prize pool that increases every time the game is played but not won. Examples include Mega Moolah or Dream Catcher.
• KYC (Know Your Customer): The mandatory process where casinos verify a player’s identity via ID and proof of address.
• Live Dealer: Games played with a real human dealer streamed via video link.
• Lobby: The main landing page of the casino where games are listed.
• Loyalty Program: A structured reward system where players climb “Tiers” (Bronze, Silver, Gold) to unlock better perks like faster withdrawals or personal account managers.

M – R: Mechanics & Regulation

• Manual Flush: A feature that allows a player to lock a withdrawal request so they cannot reverse it and gamble the money away while waiting for processing.
• Max Bet Rule: The strict limit on how much you can bet per spin while playing with bonus funds (usually $5/€5).
• Megaways™: A popular slot engine created by Big Time Gaming, where the number of symbols on each reel changes every spin, creating up to 117,649 ways to win.
• Multiplier: A feature that multiplies your winnings by a specific figure (e.g., 2x, 10x, 100x).
• No-Deposit Bonus: A small bonus (cash or spins) given to a player just for registering, requiring no financial commitment.
• Non-Sticky Bonus (Parachute): A bonus where real money and bonus funds are separated. You play with cash first and can withdraw winnings immediately if you haven’t touched the bonus funds.
• Payline: The line on which matching symbols must land to generate a win.
• Pending Period: The time a casino keeps your withdrawal in a “processing” state before sending the funds.
• Pit Boss: In land-based or live casinos, the person who supervises the dealers and tables to ensure fair play and resolve disputes.
• Provably Fair: A technology used mostly in crypto casinos that allows players to verify the randomness of every game outcome using cryptographic hashes.
• Reality Check: A pop-up notification that appears at set intervals (e.g., every hour) to remind the player how long they have been playing and how much they have won or lost.
• Reload Bonus: A bonus offered to existing players who have already made their first deposit.
• Retrigger Landing the required Scatter symbols during a Free Spins round to add more spins to your current total.
• RNG (Random Number Generator): The algorithm ensures every game outcome is random.
• Rollover: Another word for Wagering Requirement.
• RTP (Return to Player): The percentage of wagered money a slot pays back over time. Good RTP is generally considered 96%+.

S – Z: Symbols, Safety & Slang

• Scatter Symbol: A symbol that pays out or triggers bonuses regardless of paylines.
• Seed Amount: The baseline amount a Progressive Jackpot resets to after being won.
• Self-Exclusion: A tool to voluntarily block access to your gambling account for a set period (6 months to permanent).
• Session: The period of time a player spends gambling in one sitting.
• Shoe: The box that holds multiple decks of cards in Blackjack or Baccarat.
• Side Bet: An optional bet placed in addition to the main game (e.g., betting on “Perfect Pairs” in Blackjack).
• Skin: A “white label” casino that uses the same software, license, and games as other casinos but has a different brand name and logo.
• Source of Wealth (SOW): A compliance request where a casino asks a high-spending player to prove where their money comes from (e.g., payslips, inheritance, property sale) to prevent money laundering.
• Stacked Wilds: Wild symbols that appear on top of each other, covering part or all of a reel.
• Sticky Bonus (Phantom): A bonus that can be played but never withdrawn. It is removed from the balance upon cashout.
• Sticky Wilds: Wild symbols that remain in place on the screen for subsequent spins.
• Tilt: An emotional state of frustration causing a player to make bad bets to chase losses.
• Turnover: The total amount of money wagered. (See: Wagering Requirement).
• Variance (Volatility): The risk level of a game. High variance = rare, big wins. Low variance = frequent, small wins.
• Wager-Free: Bonuses where winnings are paid in cash with no playthrough requirements.
• Wagering Requirement: The multiplier (e.g., 35x) represents how many times a bonus must be played before it becomes cash.
• Whale: A very wealthy High Roller who bets massive amounts.
• Wild Symbol: A symbol that substitutes for standard symbols to create wins.
• Withdrawal Limit: A cap on how much a player can withdraw in a specific timeframe (Daily, Weekly, or Monthly).